title: Effects of creatine supplementation on oxidative stress and inflammatory markers after repeated-sprint exercise in humans.
abstract: OBJECTIVE
  The goal of this study was to evaluate the effects of creatine (Cr) supplementation on oxidative stress and inflammation markers after acute repeated-sprint exercise in humans.
  
  
  METHODS
  Twenty-five players under age 20 y were randomly assigned to two groups: Cr supplemented and placebo. Double-blind controlled supplementation was performed using Cr (0.3 g/kg) or placebo tablets for 7 d. Before and after 7 d of supplementation, the athletes performed two consecutive Running-based Anaerobic Sprint Tests (RAST). RAST consisted of six 35-m sprint runs at maximum speed with 10 sec rest between them. Blood samples were collected just prior to start of test (pre), just after the completion (0 h), and 1 h after completion.
  
  
  RESULTS
  Average, maximum, and minimum power values were greater in the Cr-supplemented group compared with placebo (P < 0.05). There were significant increases (P < 0.05) in plasma tumor necrosis factor alpha (TNF-α) and C-reactive protein (CRP) up to 1 h after acute sprint exercise in the placebo-supplemented group. Malondialdehyde, lactate dehydrogenase (LDH), catalase, and superoxide dismutase enzymes also were increased after exercise in both groups. Red blood cell glutathione was lower after exercise in both groups. Cr supplementation reversed the increase in TNF-α and CRP as well as LDH induced by acute exercise. Controversially, Cr supplementation did not inhibit the rise in oxidative stress markers. Also, antioxidant enzyme activity was not different between placebo and Cr-supplemented groups.
  
  
  CONCLUSIONS
  Cr supplementation inhibited the increase of inflammation markers TNF-α and CRP, but not oxidative stress markers, due to acute exercise.
authors.affiliation: Department of Physical Education, Faculty of Physical Education and Sport-State University of Londrina, Paraná, Brazil. deminice@ig.com.br
authors.forename: Rafael
authors.initials: R
authors.lastname: Deminice
authors.forename: Flávia Troncon
authors.initials: FT
authors.lastname: Rosa
authors.forename: Gabriel Silveira
authors.initials: GS
authors.lastname: Franco
authors.forename: Alceu Afonso
authors.initials: AA
authors.lastname: Jordao
authors.forename: Ellen Cristini
authors.initials: EC
authors.lastname: de Freitas
mesh_terms: D000293:Adolescent; D000975:Antioxidants / Q000494:pharmacology; D015415:Biomarkers / Q000097:blood; D002097:C-Reactive Protein / Q000378:metabolism; D003401:Creatine / Q000008:administration & dosage*; D019587:Dietary Supplements; D004311:Double-Blind Method; D006801:Humans; D007249:Inflammation / Q000188:drug therapy / Q000503:physiopathology; D007770:L-Lactate Dehydrogenase / Q000097:blood; D008297:Male; D008315:Malondialdehyde / Q000097:blood; D018384:Oxidative Stress / Q000187:drug effects*; D012420:Running / Q000502:physiology*; D012916:Soccer; D064133:Sports Nutritional Physiological Phenomena; D013482:Superoxide Dismutase / Q000097:blood; D014409:Tumor Necrosis Factor-alpha / Q000097:blood
chemical_list: D000975:Antioxidants; D015415:Biomarkers; D014409:Tumor Necrosis Factor-alpha; D008315:Malondialdehyde; D002097:C-Reactive Protein; D007770:L-Lactate Dehydrogenase; D013482:Superoxide Dismutase; D003401:Creatine
keywords: Creatine supplementation; Inflammation; Oxidative stress; Soccer; Sprint exercise